52 PICKERING— INTERNATIONAL SOUTHERN TELESCOPE. [April 18 



in the series of annals, giving the author as many copies as he could 

 usefully distribute. On special occasions, as during an opposition 

 of Mars, a specialist might be invited to the observatory and the 

 telescope placed, for the time, at his disposal. It would be difficult 

 to find useful work for the telescope when the moon was full. Such 

 researches as photometric measures of the relative brightness of the 

 components of close double stars and studies of the moon and planets 

 could be made at such times. 



Conclusions. 



To sum up the results of this paper, it may be said that the desire 

 to have the largest telescope in the world and to carry our knowledge 

 of the stars farther than has ever been done before, has been very 

 widespread. It would be unwise to construct a refracting telescope 

 much larger than those already made. A million and a half dollars 

 would be required to duplicate one of our present observatories of 

 the first class. A reflecting telescope of seven feet aperture, larger 

 and more powerful than any hitherto constructed, could be made at 

 a moderate price. It should be mounted in the best possible location 

 as regards climate, and preferably in the southern hemisphere, to 

 permit the study of neglected regions. Such an instrument would 

 produce, by photography, results in quality much better than can 

 be obtained elsewhere and in such quantity that no single institution 

 could discuss and publish them. These photographs should be dis- 

 tributed throughout the world, and astronomers of all countries 

 would thus be furnished with better material for study than tliey 

 could possibly obtain themselves. They would also be offered every 

 aid in discussing and publishing their conclusions. 



The estimated cost of carrying out this plan is not more than 

 half a million dollars, or one third of that of an observatory of the 

 usual form as now constructed. Not only would results be obtained 

 superior to those now secured anywhere else, but the work would be 

 planned, not by a single astronomer, but by an international com- 

 mittee of astronomers, and the results would be discussed by the 

 most distinguished specialists in each department. In this way, fol- 

 lowing the example of the great industrial enterprises of the country, 

 the plan of work would be improved continually in every detail. 



